• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1997년도 봄 학술발표회 논문집
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• pp.17-34
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• 1997

• Steel and Composite Structures
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• 제20권5호
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• pp.1043-1066
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• 2016

A new analytical solution based on a third order shear deformation theory for the problem of static analysis of cross-ply doubly-curved shells is presented. The boundary-discontinuous generalized double Fourier series method is used to solve highly coupled linear partial differential equations with the mixed type simply supported boundary conditions prescribed on the edges. The complementary boundary constraints are introduced through boundary discontinuities generated by the selected boundary conditions for the derivation of the complementary solution. The numerical accuracy of the solution is compared by studying the comparisons of deflections, stresses and moments of symmetric and anti-symmetric laminated shells with finite element results using commercially available software under uniformly distributed load. Results are in good agreement with finite element counterparts. Additional results of the symmetric and anti-symmetric laminated and sandwich shells under single point load at the center and pressure load, are presented to provide data for the unsolved boundary conditions, benchmark comparisons and verifications.

• 터널과지하공간
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• 제12권3호
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• pp.158-170
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• 2002

Shi가 개발한 불연속 변형 해석은 많은 발전이 있었지만 지금까지의 해석이 모두 평면변형률이나 평면응력을 가정한 이차원으로 이루어진 해석이다. 하지만 불연속면이 기본적으로 삼차원을 형성하므로 이차원으로 해석하는데는 한계가 있다. 삼차원의 불연속면이 안정성에 큰 영향을 미치는 사면, 지하 비축기지 등의 설계에서는 삼차원 해석에 대한 연구가 필요하다. 이에 이 연구에서는 기존 Shi가 개발한 이차원 불연속 변형 해석을 삼차원 불연속 변형 해석의 이론으로 확장하고 프로그램을 개발하여 실제 블록에 적용함으로써 개발된 이론과 프로그램의 타당성을 검증하였다. 개발한 프로그램을 이용하여 일정한 경사를 가진 블록의 미끄러짐과 쐐기의 미끄러짐을 해석하여 이론값과 정확히 일치하는 결과를 얻었다. 삼차원 이론확장과 검증을 바탕으로 향후 보다 많은 숫자의 블록에 적용하면서 해석을 할 것이다.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2007년도 특별심포지엄 논문집
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• pp.213-226
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• 2007

• 한국철도학회논문집
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• 제20권5호
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• pp.637-648
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• 2017

본 논문에서는 이전 논문에서 제시한 불연속 프리캐스트 콘크리트궤도 유한요소 해석모델과 초기 변형 및 온도 변형 분석 결과를 이용하여 초기 변형과 온도에 의한 변형이 슬래브의 응력 분포에 미치는 영향을 분석하였다. 분석 결과에 따르면 프리캐스트 콘크리트 슬래브에 이미 발생해 있는 초기 변형과 온도 경사에 의한 변형이 있는 상태에서 열차하중이 작용하는 경우에는 슬래브 중앙, 모서리 중앙, 전단포켓 코너부 등 슬래브 상부에서 최대 인장응력이 발생하게 되어 열차하중만 작용하는 경우와 매우 다른 응력 분포를 나타낸다. 따라서 불연속 프리캐스트 콘크리트 궤도의 실제 취약부의 위치와 파괴모드를 예측하기 위해서는 슬래브의 초기 변형과 온도 변형을 고려하여 열차 하중에 의한 응력을 산정해야만 한다.

• Interaction and multiscale mechanics
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• 제1권2호
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• pp.251-278
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• 2008

In this study, we investigate the discontinuous-derivative treatment at the gas-liquid interface in underwater explosion (UNDEX) problems by using the Moving Least Squares-Smoothed Particle Hydrodynamics (MLS-SPH) method, which is known as one of the particle methods suitable for problems where large deformation and inhomogeneity occur in the whole domain. Because the numerical oscillation of pressure arises from derivative discontinuity in the UNDEX analysis using the standard SPH method, the MLS shape function with Discontinuous-derivative Basis Function (DBF) that is able to represent the derivative discontinuity of field function is utilized in the MLS-SPH formulation in order to suppress the nonphysical pressure oscillation. The effectiveness of the MLS-SPH with DBF is demonstrated in comparison with the standard SPH and conventional MLS-SPH though a shock tube problem and benchmark standard problems of UNDEX of a trinitrotoluene (TNT) charge.

• 한국항해항만학회지
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• 제31권7호
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• pp.589-595
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• 2007

In the majority of previous studies on deformation of seabed structures using DEM, elements of structures have been assumed that it is composed with uniform materials or received fixed wave force, despite that actual submerged structures are composed with various size materials and influenced by complicated fluid field. The goal of this study is to develop a new model for analysis of seabed structure deformation using discontinuous structures composed with various size materials. As the first phase, a model using DEM and VOF, which can compute the deformation of submerged structures composed with various size materials, such as rubble mound structures, is proposed. A model test is carried out and then the validity of the model is discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.942-947
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• 2004

The differential equations governing free, in-plane vibrations of stepped non-circuiar arches are derived as nondimensional forms including the effects of rotatory inertia, shear deformation and axial deformation. The governing equations are solved numerically to obtain frequencies and mode shapes. The lowest four natural frequencies and mode shapes are calculated for the stepped parabolic arches with hinged-hinged, hinged-clamped, and clamped-clamped end constraints. A wide range of arch rise to span length ratios, slenderness ratios, section ratios, and discontinuous sector ratios are considered. The effect of rotatory inertia and shear deformation on natural frequencies is reported. Typical mode shapes of vibrating arches are also presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.768-771
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• 2005

The purpose of this paper is to investigate the free vibration of stepped noncircular arches. Taking into account the effects of axial deformation, rotatory inertia and shear deformation, the governing differential equations are solved numerically for the elliptic and sinusoidal geometries with hinged-hinged, hinged-clamped, and clamped-clamped end constraints. The lowest four natural frequencies are presented as functions of four non-dimensional system parameters: the arch rise to span length ratio, the slenderness ratio, the section ratio, and the discontinuous sector ratio.

• Geomechanics and Engineering
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• 제30권4호
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• pp.383-392
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• 2022

Although pipelines are composed of segmental tubes commonly connected by rubber gasket or push-in joints, current studies mainly simplified pipelines as continuous structures. Effects of joints on three-dimensional deformation mechanisms of existing pipelines due to tunnel excavation are not fully understood. By conducting three-dimensional numerical analyses, effects of pipeline burial depth, tunnel burial depth, volume loss, pipeline stiffness and joint stiffness on bending strain and joint rotation of existing pipelines are explored. By increasing pipeline burial depth or decreasing tunnel cover depth, tunneling-induced pipeline deformations are substantially increased. As tunnel volume loss varies from 0.5% to 3%, the maximum bending strains and joint rotation angles of discontinuous pipelines increase by 1.08 and 9.20 times, respectively. By increasing flexural stiffness of pipe segment, a dramatic increase in the maximum joint rotation angles is observed in discontinuous pipelines. Thus, the safety of existing discontinuous pipelines due to tunnel excavation is controlled by joint rotation rather than bending strain. By increasing joint stiffness ratio from 0.0 (i.e., completely flexible joints) to 1.0 (i.e., continuous pipelines), tunneling-induced maximum pipeline settlements decrease by 22.8%-34.7%. If a jointed pipeline is simplified as a continuous structure, tunneling-induced settlement is thus underestimated, but bending strain is grossly overestimated. Thus, joints should be directly simulated in the analysis of tunnel-soil-pipeline interaction.